Fluid propeller



Sept. 1935- K. A. MEYER El AL I 2,013,473

FLUID PROPELLER Filed Sept. 24, 1932 2 Sheets-Sheet l Ihmentor;

s attorney Sept. 3, 1935. K. A. MEYER El AL FLUID PROPELLER Filed Sept. 24, 1932 2 Sheets-Shegt 2 ZSnnentorS ya 8 z/ya 6 (ltto meg,

Patented Sept. 3, 1935 FLUID PROPELLER Karl A. Meyer and Frank A. Gauger, Milwaukee, Wis; said Meyer assignor to said Gauger Application September 24, 1932, Serial No. 634,652

8 Claims. (Cl. 170-170) ciable amount. Further, these propellers as force the air through the numerous ducts, such 5' heretofore constructed, such for example as the for example as those in a heating plant. propeller type of air fan, had a relatively small An embodiment of the invention is shown in efiiciency, which rarely reached 26%. the accompanying drawings, in which:

This invention is designed to provide a pro- Figure l is a face view of the fan with one of 0 peller type pressure fan which may be employed t e b ade b Ok aW yfor an air fan to provide a relatively high static F gu e 2 iS a fragm ta y View showing a S d pressure many times in excess of that of the orview of one of the blades. dinary type of propeller fan as heretofore Figure 3 is a sectional View on the line 3-3 known, and which is suitable for forcing air of Figure 2.

through ducts under pressure not only funcgu 4 s a sect onal View on the line 44 of 15 tioning as an air mover, but also creating a static Figure pressure suitable for this type of work, the in- Figure 5 is a view showing the pressure curve vention, however, being also applicable to fluid with respect to the radial length of one of the propellers for other uses, such as the propellers blad u h figure in in the u l f o e for boats. of the blades to show the relative places at which 20 Further objects are to provide a novel form of the different Pressures are generated. fluid propeller in which a very high eificiency is gure 6 is a dia ramma c VieW Show a secured, and in which this high efiiciency may portion of a casing or duct, indicating the air be secured by a proper design of the fan for flow and the direction thereof as generated by either high or low speeds, so that the invention e fan forming the Subject matter of this 25 is flexible and may be followed in constructing vention. fans to conform to any particular requirement Referring t e d w it W be Seen that that may be encountered. the fluid propeller or fan comprises a hub I which Further objects are to provide a propeller ay b ap as indicated at $0 that it 7 type pressure fan in which the slipping of air an e m d p a driving Shaft and u 30 around the end of the fan is prevented, and in thereto n any su ta l a n not sh w a by which the return flow of air at approximately means of keying or y means of a Set screw, or the central portion of the fan is Wholly avoided, any of the al d F this hub a such return flow greatly lessening the efiiciency p a ty O b s 3 Cl outwardly Substanof the propeller type fans heretofore known d tially radially. These blades are each of similar 35 rendering the central portion of the fan not only construction and are provided With a curving useless, even as an air mover, but permitting a lower portion or entering edge 4, see Figures 1 large waste of air backwardly through the cend 2 d h Sectional Vi ws 3 and 4. What tral portion of the fan. might be called the forward half of the blade 0 In greater detail objects of this invention are as a g adua y increasing pitch as the center is p to provide a propeller type pressure fan in which appr ed and he trailing edge is Provided W there is a regular increase and decrease of pitch a plurality of cusps 5 so as to divide the trailing as the blades of the fan are measured radially edge into a plurality of portions 6, l and 8. inwardly, the fan being so constructed that the In the form shown, two of these cusps have 5 air is directed from the fan and slightly inbeen illustrated, though one or more can be emwardly so as to build up a pressure at certain ployed depending upon the size of the fan. The definite points, and in addition, build a pressure end po 0f t fan s Provided with an upat the central portion of the fan as well, to preturned end lip 9 which prevents slipping of the vent reverse flow and thereby to avoid any loss air around the end of the fan and maintains of efiiciency whatsoever from this cause. the general pressure at this point. Further, in 50 Further objects are to provide a propeller type View of the fact that this portion of the fan 9 pressure fan which is of simple construction, merges into the portion 6, it is apparent that the which may be readily produced by ordinary air is scooped up and directed inwardly adjamethods without requiring any elaborate equipcent this point, as is obvious from the outermost merit for its production, which may be cheaply arrows l0, see Figure 6. 55

This invention relates to fluid propellers.

Fluid propellers as heretofore constructed were merely fluid movers and were not successful in creating a steady pressure of any appremade, and which is eminently suitable for use in an air or other fluid circulating system in which not only must air be moved, but in which also a static pressure must be generated by the fan to Generally the pitch of the entire blade gradually increases as the center line of the propeller is approached. It is to be noted for example that the outermost cusp 5 is set inwardly a slight amount with respect to the innermost cusp 5, as is obvious from an inspection of Figure 1. Also the portions 6, l and 8 have gradually increasing pitches due to their respective radial positions.

The latter half or the trailing portion of each fan blade is provided with a gradually increasing and decreasing pitch as the blade is measured inwardly radially towards the center. An inspection of Figures 1, 2 and 3 will clearly bring out this feature. For example, as may be seen directly from Figures 1 and 2, the portion 6 gradually increases in pitch to the cusp 5. Thereafter the trailing portion or latter half of the blade drops away from the cusp 5 with a decreasing pitch and again increases towards the second or inner cusp 5, again dropping away from this cusp and increasing as it approaches the center of the fan.

From actual measurements it has been found that the pressure curve of this fan is as shown in Figure 5, in which figure the outline of one of the blades has been incorporated in order to indicate the points at which the different pressures occur. This curve 1 l is spaced upwardly a considerable distance from the zero pressure line l2 at all points of the curve. Also it has a relatively high portion l3 adjacent the first cusp 5 and also a high portion hi adjacent the second cusp 5. Further, it is to be noted that at no portion in the curve H does it dip downwardly to contact with the zero line, but that at all portions it is spaced a material distance therefrom.

Further, this curve is the result of actual measurements of this fan in operation. It has been found from actual measurements that a high static pressure is generated very many times greater than anything heretofore possible with the usual types of propeller fans.

Further, it has been found that the air flow is inwardly at a slight angle at each of the cusps 5, as indicated by the arrows l5 and H5 in Figure 6, the transverse center line of the fan being indicated by the reference character 3'. The small curved arrows I1 and I8 indicate the air flow on opposite sides of the outermost cusp 5, and it will be seen from a comparison of the length of these two arrows in Figure 6 that there is a greater flow of air on the outer side of the cusp than on the inner side. These two curving air streams on opposite sides of the outermost cusp merge to form the air stream which is indicated by the arrow IS in Figure 6, and, as will be immediately appreciated, the air stream on the outer side of the cusp tends to continue in its last direction at the instant that it leaves the outer surface of the cusp. The inner side of the cusp appears to scoop up the air and draw it radially inwardly as the blade moves with respect to the air, as is apparent from an inspection of Figure 1, thereby also aiding in the inward direction of the air stream along the general direction indicated by the line 15.

Similarly for the inner cusp '5, the two air streams would occur as indicated by the arrows l9 and Z0 and would merge to form an air stream directed inwardly along the line of the arrow IS in Figure 6. At each of the intermediate portions 6, I and 8 the air streams are along the general'direction indicated by the arrows l0, 2| and 22.

It is apparent from Figure 6 that the inwardly directed streams of air merge and generate a pressure at the axis of the fan as well as at radially spaced portions therefrom, thereby preventing a reverse flow of air adjacent the hub or axis portion of the fan.

There is nothing in the usual type of fan to direct the air slightly inwardly, as indicated in Figure 6 for the fan forming the subject matter of this invention.

Actual tests of a fan constructed in accordance with this invention showed an efiiciency of 72%, which is a remarkable value for this type of fan. Consequently the amoimt of power required to drive the fan is very much less than anything heretofore known. The fan has been found eminently satisfactory for not only moving air through ducts as in a heating system, but also for building up a static pressure, thereby forcing the air through the ducts against resistance. Usually the propeller type of fan has not been used for this purpose and when used is of very low efficiency. However, with the fan forming the subject matter of this invention a very high efficiency is insured.

This fan has also been used very successfully as a propeller for a boat, and it has been found that the high stern wake regularly present in high speed boats is absent when this type of fan used. In other words, there is not that buildheretofo-re always occurred. The eiflciency of the fan when used as this type of fluid propeller was found to be very high, as a greatly increased speed was obtained from the boat with the same expenditure of power.

it is obvious from an inspection of Figures 3 and 4 that the leading and trailing edges of the fan could be streamlined.

It will be seen that a novel type of fluid propeller has been provided by this invention in which the fluid propeller acts not only as a fluid mover, but also builds up a static pressure very many times greater than that heretofore possible with the ordinary types of propeller fans.

Further, it will be seen that a very simple type of fluid propeller has been provided by this invention which has a high efficiency and therebymaterially reduces the requirement of power for driving the fan.

Although this invention has been described in considerable detail, it is to be understood that such description is intended as illustrative rather than limiting, as the invention may be variously embodied and is to be interpreted as claimed.

We claim:

1. A fluid propeller having a plurality of blades, said blades having a plurality of sections which have a gradually increasing pitch followed by a gradually decreasing pitch as said blades are measured radially inwardly towards the center of said propeller, each section having a leading edge portion whose pitch is indirectly proportional to its radial distance, and having an intermediate, gradually curving portion merging into the leading and trailing portions.

2. A fluid propeller for building up a static pressure, said propeller comprising a plurality of blades having a gradually increasing pitch as the blade is measured radially inwardly towards the center, and having at least one forwardly directed cusp formed in each blade, the cusp gradually merging into the adjacent portion of the blade, said cusp having a radial section gradually curving on opposite sides.

mg up of water rearwardly of the boat as has 9 3. A fluid propeller for building up a static pressure, said propeller comprising a plurality of blades having a gradually increasing pitch as the blade is measured radially inwardly towards the center, and having at least one forwardly directed cusp formed in each blade, the cusp gradually merging into the adjacent portion of the blade on each side of the cusp in a smooth concave curve, the rear face of the propeller having a double convex curve leading into said cusp.

4. A fluid propeller for building up a static pressure, said propeller comprising a plurality of blades having a gradually increasing pitch as p the blade is measured radially inwardly towards the center, and having at least one forwardly directed cusp formed in the trailing portion of each blade, the cusp gradually merging into the adjacent portion of the blade on each side of the cusp in a smooth concave curve, the rear face of the propeller following approximately the reverse contour of the front face, said propeller directing the fluid slightly inwardly towards the axis of said propeller.

5. A fluid propeller for building up a static pressure, said propeller comprising a plurality of blades having a gradually increasing pitch as the blade is measured radially inwardly towards the center, and having at least one forwardly directed cusp formed in each blade, the cusp gradually merging into the adjacent portion of the blade on opposite sides of the cusp and being free of reentrant angles, said propeller having forwardly turned lips at the outer ends of the blades.

6. A fluid propeller comprising a hub portion pitch as the blade is measured radially inwardly towards the center of the hub, each blade having a plurality of spaced cusps projecting forwardly of the trailing portion of the blade and merging gradually into the blade on opposite sides of each cusp, said cusps directing the fluid generally inwardly towards the axis of said propeller, said propeller being free of reentrant angles on its front side on opposite sides of each cusp.

'7. A fluid propeller comprising a hub portion and a plurality of radially arranged blades, each blade having a generally gradually increasing pitch as the blade is measured radially inwardly towards the center of the hub, each blade having a plurality of radially spaced cusps projecting forwardly of the blade, the cusps having a greater pitch than the remainder of the blade and each cusp having a successively greater pitch than the immediately preceding radially outwardly spaced cusp, the leading edge of each blade being free of cusps.

8. A fluid propeller comprising a hub portion and a plurality of radially arranged blades, each blade having a generally gradually increasing pitch as the blade is measured radially inwardly towards the center of the hub, each blade having a plurality of spaced cusps projecting forwardly of the trailing portion of the blade and merging gradually into the blade on opposite sides of each cusp, said cusps being formed in the trailing portion of the blade and terminating short of the leading portion of the blade, said cusps directing the fluid generally inwardly towards the axis of said propeller, said propeller having forwardly turned lips at the outer ends of the blades.

KARL A. MEYER. FRANK A. GAUGER. 

